After updating their phones, users will find a new option on the Battery page of the Settings app to turn off the feature, which Apple said "dynamically manages maximum performance to prevent unexpected shutdowns."

The feature will only be available for iPhone 6, iPhone 6 Plus, iPhone SE, iPhone 6s, iPhone 6s Plus, iPhone 7 and iPhone 7 Plus. Newer models - the iPhone 8 and X - do not include the throttling feature.

Apple apologized last year for slowing down older iPhones, a move it said was necessary to avoid unexpected shutdowns related to battery fatigue.

Many customers interpreted the move as a way for Apple to juice demand for newer iPhone models, their suspicions fueled by the fact that the company didn't initially disclose the slowdowns or its reasons for them.